The present invention is directed generally to roll casting process control, and particularly to systems that generate necessary control actions to maintain differences between desired and actual process parameter values as near to zero as possible.
Heretofore there has not been a totally integrated automatic package for continuously precisely controlling the location of the freezing front of molten metal in the bite of casting rolls, the gauge of the metal exiting the rolls compensating for the eccentricity of the rolls, and combining and decoupling various automation schemes to yield such an integrated package.
For example, U.S. Pat. No. 4,497,360 to Bercovici discloses a method of optimizing productivity of a roll casting machine by measuring the torque exerted on at least one of the rolls, the stress on roll journals, or temperature of the strip exiting the machine. Deviations from a constantly computed previous average value of one or more of the above parameters are then used to control roll speed. If the deviation exceeds a reference deviation, the casting speed of the machine is reduced until the deviation becomes less than the reference deviation. Casting speed is then increased as long as the deviation remains lower than the reference.
Published European Patent Application No. 0,138,059 shows control of solidification time and position of the freezing front of metal in the bite of the rolls of a roll casting machine by measuring a rolling torque or rolling pressure and then controlling the rotational speed of the rolls as a function of torque or pressure.